To each their own, but I won't use anything but a 25g to inject with. Sure It takes a whole minute or two to inject with more pressure, but the fact that I get pretty much zero PIP I have to deal with for the next couple days makes it well worth it.
I will take a slow injection that requires a little more pressure for no PIP any day of the week
When I started my TRT my dr was injecting me with18g and sent me home with 100, they didn't hurt at first, but after 4 months I started getting PIP, now I draw with 18 and use a 23g much nicer lol
I've never had any issues with 25g being hard to press down or take long to do so. I used pharmacy grade brand so maybe some others may be thicker than others.
I don't see how many people have trouble pushing oil through a 25g. I run it under hot water for like 30 seconds and the viscosity drops to the point that I can emty 1cc in 7-8 seconds. I'll probably only ever use a 25 because for some reason I shake quite a bit doing glutes, the needle doesn't move side to side but I turn it into a mini jackhammer pretty easily ha. Delts are very still though.
Injecting oil works great with a 23g with most compounds. 25g is ok but I agree takes a bit more to push and may cause some secondary pain from the needle jerking in and out while pushing. I heat up a damp towel in the microwave and place the syringe between it to heat up the oil. Makes it really smooth while injecting and less PIP from the hormone crashing in your muscle.